How much fertilizer per 1,000 sq ft (simple math guide)

The three numbers on every fertilizer bag (like 24-0-11) tell you the percentage of nitrogen, phosphorus, and potassium by weight. Most people have no idea how to turn those into an application rate.

The 1-pound nitrogen rule

For cool-season lawns, apply about 1 pound of actual nitrogen per 1,000 square feet per application. Divide 100 by the first number on the bag. A 24-0-11 fertilizer: 100 divided by 24 equals 4.2 pounds of product per 1,000 sq ft.

Common products

Milorganite (6-4-0): 16.7 lbs per 1,000 sq ft. Scotts Turf Builder (32-0-10): 3.1 lbs. Starter fertilizer (18-24-12): 5.6 lbs. Organic fertilizers always require heavier rates because the nitrogen percentage is lower.

How often to fertilize

Zone 7 cool-season lawns need 3-4 applications per year: early spring (March), late spring (May), early fall (September), and late fall winterizer (November). Skip summer entirely — it stresses the grass.

Why a soil test matters

General rates assume average soil. A $15 soil test tells you exactly what your lawn needs. If nitrogen is already adequate, you might need only 2 applications. If potassium is low, you need a different formula. The test pays for itself.

Grasslytics calculates exact quantities based on your lawn size and soil test. Upload your results and the app tells you what to buy and how much.